WASHINGTON � The lone suspect in a deadly shooting at the Fort Lauderdale airport in Florida is reported to be a former National Guard member who was hospitalized for a mental health evaluation last year after hearing voices that urged him to commit acts of violence.

The U.S. Federal Bureau of Investigation says it has not ruled out terrorism in the deadly shooting Friday. FBI agent George Piro said at a Friday night news conference the bureau is pursuing every possible lead, including terrorism.

Law enforcement officials holding the suspect say he is 26-year-old Esteban Santiago of Alaska who arrived at the airport Friday on a flight from Anchorage, the largest city in Alaska.

He is believed to have opened fire at the airport, killing five people and wounding eight more before being detained. Piro said the gunman had a semi-automatic handgun.

At first, police were not certain whether more than one gunman was involved, so they checked everyone closely before allowing people back into the terminal. Airport operations were shut down for hours, and flights bound for Fort Lauderdale from across the country were grounded in distant cities.

Authorities eventually said there was only one suspect, and that no shots were fired by any of the police agencies at the scene. The suspect was detained after he ran out of ammunition and lay down on the floor of the terminal, spread-eagled.

Suspect served in Iraq

Santiago is reported to be a former National Guard member serving in Puerto Rico. Last year, he voluntarily checked into a hospital for mental health evaluation. He is reported to have said he was hearing imaginary voices, some of them telling him to join the terrorist group Islamic State.

Santiago spent 10 months in Iraq in 2010 and 2011. He later joined the Army National Guard in Alaska, the largest and most remote U.S. state. He is believed to have served in the Guard there from 2014 until August last year when he was discharged for unsatisfactory performance. Law enforcement officials also said Santiago spent some time working for a security company in Anchorage.

Other accounts said Santiago was discharged from the National Guard last year for unsatisfactory performance.

The young man is reported to have checked into a hospital in Alaska voluntarily for a mental-health evaluation last year after telling authorities he had been hearing voices in his head, some of them urging him to commit acts of violence.

He also is said to have told federal agents he received messages that the U.S government was ordering him to join the terrorist group Islamic State, but there was no indication he acted on that in any way.

Law-enforcement officials at the scene of the airport shooting said they believed Santiago had traveled with a handgun in a locked case in his checked luggage � a normal practice for licensed owners of weapons. They said he retrieved the luggage after arriving in Florida and loaded the gun in a restroom before walking toward travelers waiting for their bags, where he opened fire.

'Senseless act of evil'

Florida's governor, Rick Scott, spoke to reporters several hours after the shooting, which he called a senseless act of evil, and asked for prayers for all the victims.

Scott said his staff has been in touch with airports around the state since the shooting to find out what resources they need.

My imperative is to keep everybody safe, he said. Everybody's working hard to find out exactly what happened and I don't want this to ever happen again.

President Barack Obama spoke by telephone with Scott, offering his condolences to the victims of the shooting and their families, and also pledged federal authorities' full assistance in investigating the horrific shooting.

Scott said he called President-elect Donald Trump and Vice President-elect Mike Pence about the shooting and was assured they would do everything in their power to provide whatever assistance is needed.

Obama told ABC News Friday he was heartbroken by the shooting, and added: These kinds of tragedies have happened too often during the years that I've been president. ... The pain, the grief, the shock that they [victims and witnesses] must be going through is enormous.